1. Field
This disclosure relates to a separator for a rechargeable lithium battery and a rechargeable lithium battery including the same.
2. Description of the Related Art
A conventional rechargeable lithium battery includes a separator made of a porous insulating film interposed between positive and negative electrodes. The pores of the film are impregnated by an electrolyte solution including a lithium salt dissolved therein. The non-aqueous rechargeable lithium battery has excellent high-capacity and high energy density characteristics.
However, when the positive and negative electrodes therein are repetitively contracted and expanded during the charge and discharge cycles, they may react with a separator or an electrolyte solution. As a result, the non-aqueous rechargeable lithium battery may be easily deteriorated, have internal and external short circuits, and rapidly become hot. When the battery rapidly becomes hot as aforementioned, the separator is fused and is then rapidly contracted or destroyed and thus, short-circuited again.
In order to prevent (or reduce) this problem, a conventional separator is widely formed of a porous polyethylene film having excellent shutdown characteristic, is easily handled, and has low cost. Herein, the shutdown indicates that a separator is partly fused, which closes the pores and cuts off the current when the battery is heated up due to overcharge, external or internal short circuit, and the like.
In addition, an attempt has been made to improve safety of the rechargeable lithium battery by improving heat resistance of the electrode material for the separator and the like and in particular, to secure safety even when the separator therein is sharply contracted or destroyed.